U.S. patent application number 15/169898 was filed with the patent office on 2017-05-04 for light-emitting display device and method of fabricating the same.
The applicant listed for this patent is SAMSUNG DISPLAY CO., LTD.. Invention is credited to Seung Uk NOH.
Application Number | 20170125719 15/169898 |
Document ID | / |
Family ID | 58634753 |
Filed Date | 2017-05-04 |
United States Patent
Application |
20170125719 |
Kind Code |
A1 |
NOH; Seung Uk |
May 4, 2017 |
LIGHT-EMITTING DISPLAY DEVICE AND METHOD OF FABRICATING THE
SAME
Abstract
A light-emitting display device comprises: a substrate including
a plurality of pixel areas arranged in a first direction and a
second direction intersecting the first direction; a first
electrode on the substrate in each of the plurality of pixel areas;
a plurality of pixels corresponding to the first electrode in each
of the plurality of pixel areas; a pixel defining layer on the
substrate having a pixel opening exposing the first electrode; a
lens layer on the first electrode in the pixel opening, a thickness
in a center of the lens layer being different from a thickness at
an edge of the lens layer; a planarization layer on the lens layer
in the pixel opening and having a flat surface facing away from the
lens layer; a light emitting layer on the planarization layer; and
a second electrode on the light emitting layer.
Inventors: |
NOH; Seung Uk; (Seoul,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG DISPLAY CO., LTD. |
Yongin-si |
|
KR |
|
|
Family ID: |
58634753 |
Appl. No.: |
15/169898 |
Filed: |
June 1, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 51/56 20130101;
H01L 51/0005 20130101; H01L 51/5088 20130101; H01L 27/3246
20130101; H01L 27/3211 20130101; H01L 51/5275 20130101; H01L
2227/323 20130101 |
International
Class: |
H01L 51/50 20060101
H01L051/50; H01L 51/52 20060101 H01L051/52; H01L 51/56 20060101
H01L051/56; H01L 27/32 20060101 H01L027/32 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 30, 2015 |
KR |
10-2015-0151820 |
Claims
1. A light-emitting display device, comprising: a substrate
including a plurality of pixel areas arranged in a first direction
and a second direction intersecting the first direction; a first
electrode on the substrate in each of the plurality of pixel areas;
a plurality of pixels corresponding to the first electrode in each
of the plurality of pixel areas; a pixel defining layer on the
substrate having a pixel opening exposing the first electrode; a
lens layer on the first electrode in the pixel opening, a thickness
in a center of the lens layer being different from a thickness at
an edge of the lens layer; a planarization layer on the lens layer
in the pixel opening and having a flat surface facing away from the
lens layer; a light emitting layer on the planarization layer; and
a second electrode on the light emitting layer.
2. The light-emitting display device as claimed in claim 1, wherein
a surface of the lens layer that faces the planarization layer is a
curved surface being closer to the light emitting layer at the
center than at the edge of the lens layer, and wherein the
thickness in the center of the lens layer is a largest thickness of
the lens layer and the thickness at the edge of the lens layer is a
smallest thickness of the lens layer.
3. The light-emitting display device as claimed in claim 2, wherein
the plurality of pixels include a first pixel and a second pixel
emitting light of different colors, and wherein the lens layer in
the first pixel has the largest thickness in the center of the lens
layer and the second pixel has a largest thickness of the lens
layer in the center different from the largest thickness in the
center of the lens layer in the first pixel.
4. The light-emitting display device as claimed in claim 2, wherein
the lens layer is formed by ejecting a hole injection solution
containing a hole injection material onto the first electrode and
drying the hole injection solution, and wherein the pixel defining
layer includes an insulative material that has a lyophobic property
to the hole injection solution.
5. The light-emitting display device as claimed in claim 1, wherein
a surface of the lens layer that faces the planarization layer is a
curved surface being closer to the light emitting layer at the edge
that at the center of the lens layer, and wherein the thickness in
the center of the lens layer is a smallest thickness of the lens
layer and the thickness at the edge of the lens layer is a largest
thickness of the lens layer.
6. The light-emitting display device as claimed in claim 5, wherein
the lens layer is formed by ejecting a hole injection solution
containing a hole injection material onto the first electrode and
drying the hole injection solution, and wherein the pixel defining
layer includes an insulative material that has a lyophilic property
to the hole injection solution.
7. The light-emitting display device as claimed in claim 1, wherein
the planarization layer includes a same material as the lens
layer.
8. The light-emitting display device as claimed in claim 1, wherein
the first electrode includes a transparent electrode material and
the second electrode includes a reflective electrode material.
9. A light-emitting display device, comprising: a substrate
including a plurality of pixel areas arranged in a first direction
and a second direction intersecting the first direction, the
substrate having a first surface and a second surface facing the
first surface; a first electrode on the first surface of the
substrate in each of the pixel areas; a plurality of pixels
corresponding to the first electrode in each of the plurality of
pixel areas; a pixel defining layer on the first surface of the
substrate and having a pixel opening exposing the first electrode;
a light emitting layer on the first electrode; a second electrode
on the light emitting layer; a partitioning wall on the second
surface of the substrate and having a partitioning wall opening
exposing a part of the second surface of the substrate
corresponding to the first electrode; and a lens layer on the
second surface of the substrate in the partitioning wall opening,
wherein a thickness in a center of the lens layer is different from
a thickness at an edge of the lens layer.
10. The light-emitting display device as claimed in claim 9,
wherein a surface of the lens layer exposed via the partitioning
wall opening is a curved surface closer to the light emitting layer
at the center that at the edge of the lens layer, and wherein the
thickness in the center of the lens layer is a smallest thickness
of the lens layer and the thickness at the edge of the lens layer
is a largest thickness of the lens layer.
11. The light-emitting display device as claimed in claim 10,
wherein the plurality of pixels includes a first pixel and a second
pixel emitting light of different colors, and wherein the lens
layer in the first pixel has the smallest thickness in the center
of the lens layer and the second pixel has a smallest thickness of
the lens layer in the center different from the smallest thickness
in the center of the lens layer in the first pixel.
12. The light-emitting display device as claimed in claim 10,
wherein the lens layer is formed by ejecting a lens solution
containing a lens material onto the second surface of the substrate
and drying the lens solution, and wherein the partitioning wall
includes an insulative material that has a lyophilic property to
the lens solution.
13. The light-emitting display device as claimed in claim 9,
wherein a surface of the lens layer exposed via the partitioning
wall opening is a curved surface closer to the light emitting layer
at the edge than at the center of the lens layer, and wherein the
thickness in the center of the lens layer is a largest thickness of
the lens layer and the thickness at the edge of the lens layer is a
smallest thickness of the lens layer.
14. The light-emitting display device as claimed in claim 13,
wherein the lens layer is formed by ejecting a lens solution
containing a lens material onto the second surface of the substrate
and drying the lens solution, and wherein the partitioning wall
includes an insulative material that has a lyophobic property to
the lens solution.
15. The light-emitting display device as claimed in claim 9,
wherein the first electrode includes a transparent electrode
material and the second electrode includes a reflective
material.
16. A method of fabricating a light-emitting display device, the
method comprising: forming a first electrode in each of a plurality
of pixel areas arranged on a substrate in a first direction and a
second direction intersecting the first direction such that a
corresponding plurality of pixels is formed; forming a pixel
defining layer on the substrate, the pixel defining layer defining
each of the pixels and having a pixel opening exposing the first
electrode; forming a lens layer on the first electrode in the pixel
opening, a thickness in a center of the lens layer being different
from a thickness at an edge of the lens layer; forming a
planarization layer on the lens layer in the pixel opening such
that the planarization layer has a flat surface facing away from
the lens layer; forming a light emitting layer on the planarization
layer; and forming a second electrode on the light emitting
layer.
17. The method as claimed in claim 16, wherein forming the lens
layer and forming the planarization layer includes ejecting a lens
solution into the pixel opening using an ink print method or a
nozzle print method and drying the lens solution.
18. The method as claimed in claim 17, wherein forming the lens
layer includes ejecting a hole injection solution containing a hole
injection material as the lens solution onto the first electrode
and drying the hole injection solution, and wherein the pixel
defining layer includes an insulative material that has a lyophobic
property to the hole injection solution.
19. The method as claimed in claim 17, wherein forming the lens
layer includes ejecting a hole injection solution containing a hole
injection material onto the first electrode and drying the hole
injection solution, and wherein the pixel defining layer includes
an insulative material that has a lyophilic property to the hole
injection solution.
20. The method as claimed in claim 17, wherein forming the lens
layer and forming the planarization layer are performed using a
same lens solution.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] Korean Patent Application No. 10-2015-0151820, filed on Oct.
30, 2015, in the Korean Intellectual Property Office, and entitled:
"Light-Emitting Display Device and Method of Fabricating the Same,"
is incorporated by reference herein in its entirety.
BACKGROUND
[0002] 1. Field
[0003] Exemplary embodiments relate to a light-emitting display
device and a method of fabricating the same.
[0004] 2. Description of the Related Art
[0005] Among light-emitting display devices, organic light-emitting
display devices emit light on their own. and they have wide viewing
angle, good contrast ratio, and fast response speed.
[0006] An organic light-emitting display device may include a light
emitting layer made of an organic luminescent substance between an
anode electrode and a cathode electrode. Holes injected from the
anode electrode migrate to the light emitting layer via a hole
injection layer and a hole transport layer in response to a
positive voltage applied thereto, while electrons injected from the
cathode electrode migrate to the light emitting layer via an
electron injection layer and an electron transport layer in
response to a negative voltage applied thereto. Then, the electrons
and holes recombine in the light emitting layer. As a result of the
recombination, excitons are created. The excitons emit energy in
the form of light as they change from an excited state to a ground
state in the light emitting layer, so that an image is
displayed.
[0007] An organic light-emitting display device may include a pixel
defining layer having an opening. An anode electrode formed in each
of pixels arranged in a matrix on a substrate is exposed via the
opening. On the anode electrode exposed via the pixel opening of
the pixel defining layer, a hole injection layer, a hole transport
layer, an light emitting layer, an electron transport layer, an
electron injection layer and a cathode electrode are formed in this
order.
SUMMARY
[0008] Exemplary embodiments may provide a light-emitting display
device comprising: a substrate including a plurality of pixel areas
arranged in a first direction and a second direction intersecting
the first direction; a first electrode on the substrate in each of
the plurality of pixel areas; a plurality of pixels corresponding
to the first electrode in each of the plurality of pixel areas; a
pixel defining layer on the substrate having a pixel opening
exposing the first electrode; a lens layer on the first electrode
in the pixel opening, a thickness in a center of the lens layer
being different from a thickness at an edge of the lens layer; a
planarization layer on the lens layer in the pixel opening and
having a flat surface facing away from the lens layer; a light
emitting layer on the planarization layer; and a second electrode
on the light emitting layer.
[0009] A surface of the lens layer that faces the planarization
layer may be a curved surface being closer to the light emitting
layer at the center than at the edge of the lens layer, and the
thickness in the center of the lens layer may be a largest
thickness of the lens layer and the thickness at the edge of the
lens layer may be a smallest thickness of the lens layer.
[0010] The plurality of pixels may include a first pixel and a
second pixel emitting light of different colors, and the lens layer
in the first pixel may have the largest thickness in the center of
the lens layer, and the second pixel may have a largest thickness
of the lens layer in the center different from the largest
thickness in the center of the lens layer in the first pixel.
[0011] The lens layer may be formed by ejecting a hole injection
solution containing a hole injection material onto the first
electrode and drying the hole injection solution, and the pixel
defining layer may include an insulative material that has a
lyophobic property to the hole injection solution.
[0012] A surface of the lens layer that faces the planarization
layer may be a curved surface being closer to the light emitting
layer at the edge that at the center of the lens layer, and the
thickness in the center of the lens layer may be a smallest
thickness of the lens layer and the thickness at the edge of the
lens layer may be a largest thickness of the lens layer.
[0013] The lens layer may be formed by ejecting a hole injection
solution containing a hole injection material onto the first
electrode and drying the hole injection solution, and the pixel
defining layer may include an insulative material that has a
lyophilic property to the hole injection solution.
[0014] The planarization layer may include a same material as the
lens layer.
[0015] The first electrode may include a transparent electrode
material, and the second electrode may include a reflective
electrode material.
[0016] Exemplary embodiments may also provide a light-emitting
display device comprising: a substrate including a plurality of
pixel areas arranged in a first direction and a second direction
intersecting the first direction, the substrate having a first
surface and a second surface facing the first surface; a first
electrode on the first surface of the substrate in each of the
pixel areas; a plurality of pixels corresponding to the first
electrode in each of the plurality of pixel areas; a pixel defining
layer on the first surface of the substrate and having a pixel
opening exposing the first electrode; a light emitting layer on the
first electrode; a second electrode on the light emitting layer; a
partitioning wall on the second surface of the substrate and having
a partitioning wall opening exposing a part of the second surface
of the substrate corresponding to the first electrode; and a lens
layer on the second surface of the substrate in the partitioning
wall opening, wherein a thickness in a center of the lens layer is
different from a thickness at an edge of the lens layer.
[0017] A surface of the lens layer exposed via the partitioning
wall opening may be a curved surface closer to the light emitting
layer at the center that at the edge of the lens layer. and the
thickness in the center of the lens layer may be a smallest
thickness of the lens layer and the thickness at the edge of the
lens layer may be a largest thickness of the lens layer.
[0018] The plurality of pixels may include a first pixel and a
second pixel emitting light of different colors, and the lens layer
in the first pixel may have the smallest thickness in the center of
the lens layer, and the second pixel may have a smallest thickness
of the lens layer in the center different from the smallest
thickness in the center of the lens layer in the first pixel.
[0019] The lens layer may be formed by ejecting a lens solution
containing a lens material onto the second surface of the substrate
and drying the lens solution, and the partitioning wall may include
an insulative material that has a lyophilic property to the lens
solution.
[0020] A surface of the lens layer exposed via the partitioning
wall opening may be a curved surface closer to the light emitting
layer at the edge than at the center of the lens layer, and the
thickness in the center of the lens layer may be a largest
thickness of the lens layer and the thickness at the edge of the
lens layer may be a smallest thickness of the lens layer.
[0021] The lens layer may be formed by ejecting a lens solution
containing a lens material onto the second surface of the substrate
and drying the lens solution, and the partitioning wall may include
an insulative material that has a lyophobic property to the lens
solution.
[0022] The first electrode may include a transparent electrode
material, and the second electrode may include a reflective
material.
[0023] Exemplary embodiments may also provide a method of
fabricating a light-emitting display device comprising: forming a
first electrode in each of a plurality of pixel areas arranged on a
substrate in a first direction and a second direction intersecting
the first direction such that a corresponding plurality of pixels
is formed; forming a pixel defining layer on the substrate, the
pixel defining layer defining each of the pixels and having a pixel
opening exposing the first electrode; forming a lens layer on the
first electrode in the pixel opening, a thickness in a center of
the lens layer being different from a thickness at an edge of the
lens layer; forming a planarization layer on the lens layer in the
pixel opening such that the planarization layer has a flat surface
facing away from the lens layer; forming a light emitting layer on
the planarization layer; and forming a second electrode on the
light emitting layer.
[0024] The forming the lens layer and the forming the planarization
layer may include ejecting a lens solution into the pixel opening
using an ink print method or a nozzle print method and drying the
lens solution.
[0025] The forming the lens layer may include ejecting a hole
injection solution containing a hole injection material as the lens
solution onto the first electrode and drying the hole injection
solution, and the pixel defining layer may include an insulative
material that has a lyophobic property to the hole injection
solution.
[0026] The forming the lens layer may include ejecting a hole
injection solution containing a hole injection material onto the
first electrode and drying the hole injection solution, and the
pixel defining layer may include an insulative material that has a
lyophilic property to the hole injection solution.
[0027] The forming the lens layer and the forming the planarization
layer may be performed using the same lens solution.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Features will become apparent to those of ordinary skill in
the art by describing in detail exemplary embodiments with
reference to the attached drawings in which:
[0029] FIG. 1 illustrates a schematic plan view showing pixels of a
light-emitting display device according to an exemplary
embodiment;
[0030] FIG. 2 illustrates a cross-sectional view taken along line
I-I' of FIG. 1;
[0031] FIG. 3 illustrates an enlarged cross-sectional view of
portion A of FIG. 2;
[0032] FIG. 4 illustrates a cross-sectional view of a portion of a
light-emitting display device according to another exemplary
embodiment, which corresponds to that shown in FIG. 2;
[0033] FIG. 5 illustrates an enlarged cross-sectional view of
portion B of FIG. 4;
[0034] FIG. 6 illustrates a cross-sectional view of a portion of a
light-emitting display device according to yet another exemplary
embodiment, which corresponds to that shown in FIG. 2;
[0035] FIG. 7 illustrates an enlarged cross-sectional view of
portion C of FIG. 6;
[0036] FIG. 8 illustrates a cross-sectional view of a portion of a
light-emitting display device according to still another exemplary
embodiment, which corresponds to that shown in FIG. 2;
[0037] FIG. 9 illustrates a cross-sectional view of a portion of a
light-emitting display device according to yet another exemplary
embodiment, which corresponds to that shown in FIG. 2; and
[0038] FIGS. 10 to 17 illustrate cross-sectional views and
perspective views for illustrating processes of a method for
fabricating a light-emitting display device according to an
exemplary embodiment.
DETAILED DESCRIPTION
[0039] Example embodiments will now be described more fully
hereinafter with reference to the accompanying drawings; however,
they may be embodied in different forms and should not be construed
as limited to the embodiments set forth herein. Rather, these
embodiments are provided so that this disclosure will be thorough
and complete, and will fully convey exemplary implementations to
those skilled in the art.
[0040] In the drawing figures, the dimensions of layers and regions
may be exaggerated for clarity of illustration. It will also be
understood that when a layer or element is referred to as being
"on" another layer or substrate, it can be directly on the other
layer or substrate, or intervening layers may also be present.
Further, it will be understood that when a layer is referred to as
being "under" another layer, it can be directly under, and one or
more intervening layers may also be present. In addition, it will
also be understood that when a layer is referred to as being
"between" two layers, it can be the only layer between the two
layers, or one or more intervening layers may also be present.
[0041] It will be understood that, although the terms first,
second, third etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer or section from another element,
component, region, layer or section. Thus, a first element,
component, region, layer or section discussed below could be termed
a second element, component, region, layer or section. Like
reference numerals refer to like elements throughout.
[0042] FIG. 1 is a schematic plan view showing pixels of a
light-emitting display device according to an exemplary embodiment.
FIG. 2 is a cross-sectional view taken along line I-I' of FIG. 1.
FIG. 3 is an enlarged cross-sectional view of portion A of FIG.
2.
[0043] Referring to FIGS. 1 and 3, a light-emitting display device
100 according to an exemplary embodiment may include a substrate
105, a first electrode 110, a pixel defining layer 120, a lens
layer 130, a planarization layer 140, a hole transport layer 150, a
light emitting layer 160, an electron transport layer 170, an
electron injection layer 180 and a second electrode 190. The
elements may be stacked on one another in the above-mentioned order
in the z-direction of FIG. 2, for example.
[0044] The substrate 105 may include a display area DA where a
plurality of pixels P for displaying images may be defined, and a
non-display area NDA located at the outer periphery of the display
area DA. The plurality of pixels P may be arranged in a matrix
along a first direction X and a second direction Y which intersects
the first direction X and may include a first pixel P1, a second
pixel P2 and a third pixel P3. For example, the first pixel P1 may
be a red pixel for emitting light of a red color, the second pixel
P2 may be a green pixel for emitting light of a green color, and
the third pixel P3 may be a blue pixel for emitting light of a blue
color.
[0045] Although the plurality of pixels P of FIG. 1 may include the
first pixel P1, the second pixel P2 and the third pixel P3 that
emit light of three different colors, exemplary embodiments are not
limited thereto. For example, the plurality of pixels P may include
the first pixel P1 and the second pixel P2 that emit light of two
different colors. Although the pixels P arranged in the second
direction Y may emit light of the same color while the pixels P
arranged in the first direction X may emit light of different
colors in FIG. 1, exemplary embodiments are not limited
thereto.
[0046] The substrate 105 may include a first surface 105a and a
second surface 105b opposed to the first surface 105a. The
substrate 105 may be made of a transparent glass material composed
mainly of transparent SiO.sub.2, for example. In some embodiments,
the substrate 105 may be made of an opaque material or a plastic
material, for example. In addition, the substrate 105 may be a
flexible substrate.
[0047] The substrate 105 may include other elements disposed on the
first surface 105a. Other elements may include lines, electrodes,
insulation films, etc. In some embodiments, the substrate 105 may
include a plurality of thin-film transistors (TFT) disposed on the
first surface 105a. Drain electrodes of at least some of the
plurality of thin-film transistors may be electrically connected to
the first electrodes 110, respectively. Each of the thin-film
transistors may include an active region made of, for example,
amorphous silicon, polycrystalline silicon or monocrystalline
silicon, etc. In an alternative embodiment, each of the thin-film
transistors may include an active region made of an oxide
semiconductor, for example.
[0048] The first electrode 110 may be disposed on the first surface
105a of the substrate 105 for every pixel P. The first electrode
110 may be an anode electrode for injecting holes or a cathode
electrode for injecting electrons into the light emitting layer 160
upon receiving a signal applied to the drain electrode of each of
the thin-film transistors. In the exemplary embodiment, the first
electrode 110 is the anode electrode.
[0049] The first electrode 110 may be used as a transparent
electrode, a reflective electrode or transflective electrode. When
the first electrode 110 is used as a transparent electrode, it may
be made of a transparent electrode material such as, for example,
indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO)
or In.sub.2O.sub.3. When the first electrode 110 is used as a
reflective electrode, it may be made by forming a reflective film
with a reflective electrode material, such as, for example, Ag, Mg,
Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a compound thereof and then
forming ITO, IZO, ZnO or In.sub.2O.sub.3 thereon. When the first
electrode 110 is used as a reflective electrode, it may be made by
forming a reflective film with a reflective electrode material,
such as, for example, Ag. Mg, Al, Pt. Pd, Au. Ni, Nd. Ir. Cr or a
compound thereof and then forming ITO, IZO, ZnO or In.sub.2O.sub.3
thereon. The first electrode 110 may be formed by, but is not
limited to, a photolithography method, for example.
[0050] The first electrode 110 may be used as a transparent
electrode when light-emitting display device 100 is a bottom
emission display device in which light emitted from the light
emitting layer 160 exits toward the first electrode 110. In
addition, the first electrode 110 may be used as a reflective
electrode when light-emitting display device 100 is a top emission
display device in which light emitted from the light emitting layer
160 exits toward the second electrode 190. In the exemplary
embodiment, the first electrode is used as a transparent electrode
and the light-emitting display device 100 is a bottom emission
display device.
[0051] The pixel defining layer 120 may be disposed on the first
surface 105a of the substrate 105 with a pixel opening 121 in which
the first electrode 110 may be exposed, and which may define each
of the pixels P on the first surface 105a of the substrate 105. The
pixel defining layer 120 may be made of an insulative material, for
example.
[0052] According to the exemplary embodiment, the lens solution
130a (see FIG. 12) has a lyophobic property to the pixel defining
layer 120, such that the lens layer 130 has the largest thickness
T1 in its center and the smallest thickness T2 at its edge. The
lens layer 130 may be produced via the process of forming the lens
layer 130 including ejecting a lens solution containing a lens
material 130a into the pixel opening 121 in the pixel defining
layer 120 using an inkjet print method or a nozzle print method and
drying the lens solution 130a. To this end, the pixel defining
layer 120 may be made of an insulative material so that the contact
angle made by the pixel defining layer 120 and the lens solution
130a (see FIG. 12) is about 50.degree. or greater. The pixel
defining layer 120 may be made of an organic insulative material
such as a polymer resin containing fluorine, e.g., at least one of
benzocyclobutane (BCB), polyimide (PI), polyamide (PA), acryl
resin, and phenol resin. The pixel defining layer 120 may be formed
by, but is not limited to, a photolithography method, for example.
The inkjet print method may be carried out, for example, by
dropping droplets of a printing ink onto a desired location. The
nozzle print method may be carried out, for example, by flowing a
print solution along a path passing through a desired location.
[0053] The lens layer 130 may be disposed on the first electrode
110 in the pixel opening 121. The thickness of the lens layer 130
in its center may be different from the thickness at its edge. For
example, the lens layer 130 may have the largest thickness T1 in
the center and may have the smallest thickness T2 at the edge. A
surface of the lens layer 130 facing the first electrode 110 may be
a flat surface. The other surface of the lens layer 130, i.e., the
surface facing the planarization layer 140 may be a curved surface
being away from light emitting layer 160 as it goes from the center
to the edge of the lens layer 130, for example, the curved surface
may be thicker in the center. The lens layer 130 may have the
curved surface so that it works as a convex lens. The lens layer
130 may concentrate the light generated in the light emitting layer
160 onto the substrate 105, thereby improving light extraction
efficiency of the light-emitting display device 100. Accordingly,
the voltage applied to the first electrode 110 and the second
electrode 190 for generating light in the light emitting layer 160
may be reduced, and thus the light-emitting display device 100 may
be driven at a lower power.
[0054] The lens layer 130 may be formed by ejecting a lens solution
130a (see FIG. 12) containing a lens material into the pixel
opening 121 in the pixel defining layer 120 by using an inkjet
print method or a nozzle print method, for example, and drying the
lens solution 130a. When the lens layer 130 is formed by using an
inkjet print method or a nozzle print method, it is possible to
form the lens layer 130 in a desired shape by adjusting a contact
angle made by the pixel defining layer 120 and the lens
solution.
[0055] For example, in FIG. 2, the pixel defining layer 120 may be
an insulative material and the contact angle made by the pixel
defining layer 120 and the lens solution 130a (see FIG. 12) may be
about 50.degree. or greater. As a result, the pixel defining layer
120 may have a lyophobic property to the lens solution 130a (see
FIG. 12). Accordingly, the lens solution 130a (see FIG. 13) may be
dried without spreading out to the edge of the pixel opening121 of
the pixel defining layer 120, so that the lens layer 130 has a
convex shape with the center thicker than the edge.
[0056] The lens layer 130 may be formed by using a hole injection
solution containing a hole injection material as the lens solution
130a (see FIG. 12). The hole injection solution may be ejected onto
the first electrode 110 and dried. Accordingly, the lens layer 130
may work as a hole injection layer.
[0057] The hole injecting layer may be a buffer layer for lowering
the energy barrier between the first electrode 110 and the hole
transport layer 150 and may facilitate injection of holes supplied
from the first electrode 110 into the hole transport layer 150. The
hole injection material may be made of, but is not limited to, an
organic compound such as, for example,
MTDATA(4,4',4''-tris(3-methylphenylphenylamino)triphenylamine),
CuPc(copper phthalocyanine) or
PEDOT/PSS(poly(3,4-ethylenedioxythiophene)/polystyrene
sulfonate).
[0058] The planarization layer 140 may be disposed on the lens
layer 130 in the pixel opening 121 and may have a flat surface. The
planarization layer 140 may contain the same material as that of
the lens layer 130 and may work as the hole injection layer
together with the lens layer 130. The planarization layer 140 may
allow the hole injection layer to have a uniform thickness.
[0059] The planarization layer 140 may be formed by ejecting a lens
solution 140a (see FIG. 14) containing a lens material into the
pixel opening 121 in the pixel defining layer 120 by using an
inkjet print method or a nozzle print method, for example, and
drying the lens solution 140a. The lens solution 140a (see FIG. 14)
used in forming the planarization layer 140 may be a hole injection
solution containing a hole injection material, for example.
[0060] Since the lens solution 140a (see FIG. 14) used in forming
the planarization layer 140 may be the same as the lens solution
130a (see FIG. 12) used in forming the lens layer 130. the lens
solution 140a (see FIG. 14) may not spread out to the edge of the
pixel opening121 of the pixel defining layer 120, so that the
planarization layer 140 may have a shape with the center thicker
than the edge. However, the planarization layer 140 may have a flat
surface by adjusting drying conditions, such as adjusting a
pressure for drying the lens solution 140a (see FIG. 14).
[0061] The hole transport layer 150 may be disposed on the
planarization layer 140 in the pixel opening121 of the pixel
defining layer 120. The hole transport layer 150 may have a uniform
thickness on the planarization layer 140. The hole transporting
layer 150 may be formed by, but is not limited to, an inkjet print
method or a nozzle print method. For example, the hole transport
layer 150 may be formed by a deposition method.
[0062] The hole transport layer 150 may deliver holes supplied via
the lens layer 130 and the planarization layer 140 to the light
emitting layer 160. The hole transport layer 150 may be made of a
hole transport material having an electric conductivity lower than
that of the hole injection layer. The hole transport layer 150 may
be made of, but is not limited to, an organic compound such as, for
example,
TPD(N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-bi-phenyl-4,4'-diamine)
or NPB(N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine).
[0063] The light emitting layer 160 may be disposed on the hole
transport layer 150 in the pixel opening 121 of the pixel defining
layer 120. The light emitting layer 160 may have a uniform
thickness on the hole transport layer 150. The light emitting layer
160 may be formed by, but is not limited to, an inkjet print method
or a nozzle print method. For example, the light emitting layer 160
may be formed by a deposition method.
[0064] The light emitting layer 160 may emit light as the holes
supplied from the first electrode 110 and the electrons supplied
from the second electrode 190 recombine. For example, the holes and
the electrons may be supplied into the light emitting layer 160 and
may recombine to form excitons. The excitons may emit energy in the
form of light as they change from an excited state to a ground
state in the light emitting layer 160. The light emitting layer 160
may include a red light emitting layer emitting layer of a red
color, a green light emitting layer emitting layer of a green
color, and a blue light emitting layer emitting layer of a blue
color.
[0065] The red light emitting layer may include a red luminous
material or may include a host and a red dopant. The host of the
red light emitting layer may include, but is not limited to,
Alq3(tris(8-quinolinolate)aluminum),
CBP(4,4'-N,N'-dicarbazol-biphenyl), PVK(ploy(n-vinylcarbazole)),
ADN(9,10-Di(naphthyl-2-yl)anthrace),
TCTA(4,4',4''-tris(N-carbazolyl)triphenylamine),
TPBI(1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene),
TBADN(3-tert-butyl-9,10-di(naphth-2-yl) anthracene),
E3(ter-fluorene), DSA(distyrylarylene), etc. The red dopant may
include, but is not limited to, PtOEP, Ir(piq)3, Btp2Ir(acac).
[0066] The green light emitting layer may include a green luminous
material or may include a host and a green dopant. The host of the
red light emitting layer may be used as the host of the green light
emitting layer. In addition, the green dopant may include, but is
not limited to, Ir(ppy)3, Ir(ppy)2(acac), Ir(mpyp)3.
[0067] The blue light emitting layer may include a blue luminous
material or may include a host and a blue dopant. The host of the
red light emitting layer may be used as the host of the blue light
emitting layer. In addition, the blue dopant may include, but is
not limited to, F2Irpic, (F2ppy)2Ir(tmd), Ir(dfppz)3, ter-fluorene,
DPAVBi(4,4'-bis(4-diphenylaminostyryl) biphenyl),
TBPe(2,5,8,11-tetra-ti-butyl pherylene), etc.
[0068] The electron transport layer 170 may be disposed on the
light emitting layer 160. The electron transport layer 170 delivers
holes supplied from the second electrode 190 via the electron
injection layer 180 to the light emitting layer 160. The electron
transport layer 170 may be made of, but is not limited to, an
organic compound such as, for example,
Bphen(4,7-diphenyl-1,10-phenanthroline),
BAlq(aluminum(III)bis(2-methyl-8-hydroxyquinolinato)4-phenylphenolate),
Alq3(tris(8-quinolinolate)aluminum),
Bebq2(berylliumbis(benzoquinolin-10-olate),
TPBI(1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene). The electron
transport layer 170 may be formed by, but is not limited to, a
deposition process.
[0069] The electron injection layer 180 may be disposed on the
electron transport layer 170. The electron injecting layer 180 may
be a buffer layer for lowering the energy barrier between the
electron transport layer 170 and the second electrode 190 and may
facilitate injection of electrons supplied from the second
electrode 190 into the electron transport layer 170. The electron
injection layer 180 may be formed by, but is not limited to, LiF or
CsF. The electron injection layer 180 may be formed by, but is not
limited to, a deposition method.
[0070] The second electrode 190 may be disposed on the electron
injection layer 180 and may be a cathode electrode for supplying
electrons or an anode electrode for supplying holes into the light
emitting layer 160. Like the first electrode 110, the second
electrode 190 may be used as a transparent electrode, a reflective
electrode or transflective electrode. The second electrode 190 may
be formed by, but is not limited to, a deposition process. As the
light-emitting display device 100 according to the exemplary
embodiment is a bottom emission display device, the second
electrode 109 may be used as a reflective electrode.
[0071] The light-emitting display device 100 may further include a
sealing substrate on the second electrode 190. The sealing
substrate may be an insulative substrate. A spacer may be disposed
between the second electrode 190 on the pixel defining layer 120
and the sealing substrate. In some embodiments, the sealing
substrate may be eliminated. In that case, a sealing film made of
an insulative material may cover the entire structure to protect
it.
[0072] As described above, according to the exemplary embodiment,
the light-emitting display device 100 may improve its light
extraction efficiency by concentrating the light generated in the
light emitting layer 160 onto the substrate 105 by virtue of the
lens layer 130 that is disposed on the first electrode 110 in the
pixel opening 121 and that works as a convex lens. Accordingly, the
voltage applied to the first electrode 110 and the second electrode
190 for generating light in the light emitting layer 160 may be
reduced and. thus, the light-emitting display device 100 may be
driven at a lower power.
[0073] In addition, according to the exemplary embodiment, the
light-emitting display device 100 may improve the luminous
efficiency by implementing a hole injection layer having a uniform
thickness, with the lens layer 130 working as a convex lens in the
pixel opening 121 and the planarization layer 140 disposed on the
lens layer 130, thereby flowing a uniform current via the first
electrode 110. As a result, the display quality of the
light-emitting display device 100 may be improved.
[0074] FIG. 4 is a cross-sectional view of a portion of a
light-emitting display device according to another exemplary
embodiment, which corresponds to that shown in FIG. 2. FIG. 5 is an
enlarged cross-sectional view of portion B of FIG. 4.
[0075] Referring to FIGS. 4 and 5, a light-emitting display 200
according to another exemplary embodiment may be substantially
identical to the light-emitting display device 100 shown in FIGS. 1
to 3 except for a lens layer 230, a planarization layer 240, a hole
transport layer 250, a light emitting layer 260, an electron
transport layer 270, an electron injection layer 280 and a second
electrode 290. Therefore, the lens layer 230, the planarization
layer 240, the hole transport layer 250, the light emitting layer
260, the electron transport layer 270, the electron injection layer
280 and the second electrode 290 of the light-emitting display
device 200 according to the exemplary embodiment will be
described.
[0076] The light-emitting display device 200 may include a
substrate 105, a first electrode 110, a pixel defining layer 120, a
lens layer 230, a planarization layer 240, a hole transport layer
250, a light emitting layer 260, an electron transport layer 270,
an electron injection layer 280 and a second electrode 290. The
elements may be stacked on one another in the above-mentioned order
in the z-direction of FIG. 4, for example.
[0077] The lens layer 230 may be similar to the lens layer 130
shown in FIG. 2. However, the size of the lens layer 230 in some
pixels differs from that of the other pixels. For example, the size
of the lens layer 230 in the first pixel P1 or the second pixel P2
may differ from the size of the lens layer 230 in the third pixel
P3. In this regard, the emission efficiency of the light emitted
from the light emitting layer 260 in the third pixel P3 may be
lower than the emission efficiency of the light emitted from the
light emitting layer 260 in the first pixel P1 and the second pixel
P2. For example, the light emitting layer 260 in the first pixel P1
may be a red light emitting layer for emitting light of a red
color, the light emitting layer 260 in the second pixel P2 may be a
green light emitting layer for emitting light of a green color, and
the light emitting layer 260 in the third pixel P3 may be a blue
light emitting layer for emitting light of a blue color.
[0078] For example, the lens layer 230 in the first pixel P1 or the
second pixel P2 may have the largest thickness T1 (see FIG. 3) in
its center and have the smallest thickness T2 at its edge, like the
lens layer 130 shown in FIG. 3. In contrast, the lens layer 230 in
the third pixel P3 may have the largest thickness T21 in its center
and may have the smallest thickness T22 at its edge. The largest
thickness T21 of the lens layer 230 in the third pixel P3 may be
larger than the largest thickness T1 (see FIG. 3) of the lens layer
130 shown in FIG. 3. The smallest thickness T22 of the lens layer
230 in the third pixel P3 may be smaller than the smallest
thickness T2 (see FIG. 3) of the lens layer 130 shown in FIG.
3.
[0079] The lens layer 230 increases the light extraction efficiency
by concentrating the light emitted from the light emitting layer
260 onto the substrate 105 in the third pixel P3, where the
emission efficiency of the light emitted from the light emitting
layer 260 is lower than that of the first pixel P1 or the second
pixel P2. By doing so, the light extraction efficiency of light
emitted toward the substrate 105 via the lens layer 230 may be
uniform across the first pixel P1, the second pixel P2 and the
third pixel P3.
[0080] The planarization layer 240 may be similar to the
planarization layer 140 shown in FIG. 2. However, the planarization
layer 240 disposed in the pixel P3 may be at a higher position than
the planarization layer 240 disposed in the first pixel P1 or the
second pixel P2.
[0081] The hole transport layer 250 may be similar to the hole
transport layer 150 shown in FIG. 2. However, the hole transport
layer 250 disposed in the pixel P3 may be at a higher position than
the hole transport layer 250 disposed in the first pixel P1 or the
second pixel P2.
[0082] The light emitting layer 260 may be similar to the light
emitting layer 160 shown in FIG. 2. However, the light emitting
layer 260 disposed in the pixel P3 may be at a higher position than
the light emitting layer 260 disposed in the first pixel P1 or the
second pixel P2.
[0083] The electron transport layer 270 may be similar to the
electron transport layer 170 shown in FIG. 2. However, the electron
transport layer 270 disposed in the pixel P3 may be at a higher
position than the electron transport layer 270 disposed in the
first pixel P1 or the second pixel P2.
[0084] The electron injection layer 280 may be similar to the
electron injection layer 180 shown in FIG. 2. However, the electron
injection layer 280 disposed in the pixel P3 may be at a higher
position than the electron injection layer 280 disposed in the
first pixel P1 or the second pixel P2.
[0085] The second electrode 290 may be similar to the second
electrode 190 shown in FIG. 2. However, the part of the second
electrode 290 disposed in the pixel P3 may be at a higher position
than the part of the second electrode 290 disposed in the first
pixel P1 or the second pixel P2.
[0086] According to the exemplary embodiment, the light-emitting
display device 200 may include the lens layer 230 having different
sizes in some pixels, so that it is possible to make the extraction
efficiency of light emitted toward the substrate 105 via the lens
layer 230 uniform across the pixels having different emission
efficiencies of the light emitted from the light emitting layer
260.
[0087] FIG. 6 is a cross-sectional view of a portion of a
light-emitting display device according to still another exemplary
embodiment, which corresponds to that shown in FIG. 2. FIG. 7 is an
enlarged cross-sectional view of portion C of FIG. 6.
[0088] Referring to FIGS. 6 and 7, a light-emitting display 300
according to yet another exemplary embodiment may be substantially
identical to the light-emitting display device 100 shown in FIGS. 1
to 3 except for a pixel defining layer 320, a lens layer 330, a
planarization layer 340, a hole transport layer 350, a light
emitting layer 360, an electron transport layer 370, an electron
injection layer 380 and a second electrode 390. Therefore, the lens
layer 330, the planarization layer 340, the hole transport layer
350, the light emitting layer 360, the electron transport layer
370, the electron injection layer 380 and the second electrode 390
of the light-emitting display device 300 according to the exemplary
embodiment will be described.
[0089] The light-emitting display device 300 may include a
substrate 105, a first electrode 110, a pixel defining layer 320, a
lens layer 330, a planarization layer 340, a hole transport layer
350, a light emitting layer 360, an electron transport layer 370,
an electron injection layer 380 and a second electrode 390. The
elements may be stacked on one another in the above-mentioned order
in the z-direction of FIG. 6, for example.
[0090] The pixel defining layer 320 may be disposed on the first
surface 105a of the substrate 105 with a pixel opening 321 exposing
the first electrode 110 and defining each of the pixels P (see FIG.
1) on the first surface 105a of the substrate 105. The pixel
defining layer 320 may be made of an insulative material, for
example.
[0091] According to the exemplary embodiment, the lens solution has
a lyophilic property to the pixel defining layer 320 such that, in
the process of forming the lens layer 330, the lens layer 330 may
be formed such that it has the smallest thickness T31 in its center
and the largest thickness T32 at the edge. The lens layer being
formed by ejecting a lens solution containing a lens material into
the pixel opening 121 of the pixel defining layer 320 using an
inkjet print method or a nozzle print method and drying it. To this
end, the pixel defining layer 320 may be made of an insulative
material so that the contact angle made by the pixel defining layer
320 and the lens solution may be about 10.degree. or less. The
pixel defining layer 320 may be made of an organic insulative
material, e.g., at least one of benzocyclobutane (BCB), polyimide
(PI), polyamide (PA), acryl resin and phenol resin, or may be made
of an inorganic insulative material, e.g., at least one of silicon
oxide, silicon nitride and silicon oxynitride. The pixel defining
layer 320 may be formed by, but is not limited to, a
photolithography method.
[0092] The lens layer 330 may be disposed on the first electrode
110 in the pixel opening 321. The thickness of the lens layer 130
in its center may be different from the thickness at its edge. For
example, the lens layer 330 may have the smallest thickness T31 in
the center and may have the largest thickness T32 at the edge. A
surface of the lens 330 facing the first electrode 110 may be a
flat surface. The other surface of the lens layer 330, i.e., the
surface facing the planarization layer 340 may be a curved surface
being closer to the light emitting layer 160 as it goes from the
center to the edge of the lens layer 330. For example, the curved
surface may be thicker at the edge. The lens layer 330 may have the
curved surface so that it works as a concave lens. The lens layer
330 diffuses the light generated in the light emitting layer 360
toward the substrate 105, thereby improving viewing angle of the
light-emitting display device 300.
[0093] The lens layer 330 may be formed by ejecting a lens solution
containing a lens material into the pixel opening 121 of the pixel
defining layer 320 by using an inkjet print method or a nozzle
print method, for example, and drying it . Since the lens layer 330
is formed by using an inkjet print method or a nozzle print method,
it is possible to form the lens layer 130 in a desired shape by
adjusting a contact angle made by the pixel defining layer 320 and
the lens solution.
[0094] For example, in FIG. 6, the pixel defining layer 320 may be
an insulative material such that the contact angle made by the
pixel defining layer 320 and the lens solution may be about
10.degree. or less. As a result, the pixel defining layer 320 has a
lyophilic property to the lens solution. Accordingly, the lens
solution may be dried in the pixel opening 321 of the pixel
defining layer 320 in a shape spreading out to the edge, so that
the lens layer 330 has a concave shape with the center thinner than
the edge.
[0095] The lens layer 330 may be formed by using a hole injection
solution containing a hole injection material as the lens solution
and the hole injection solution may be ejected onto the first
electrode 110 and dried. Accordingly, the lens layer 330 may work
as a hole injection layer.
[0096] The planarization layer 340 may be disposed on the lens
layer 330 in the pixel opening 321 and may have a flat surface. The
planarization layer 340 may contain the same material as that of
the lens layer 330 and may work as the hole injection layer
together with the lens layer 330. The planarization layer 340 may
allow the hole injection layer to have a uniform thickness.
[0097] The planarization layer 340 may be formed by ejecting a lens
solution containing a lens material into the pixel opening 321 of
the pixel defining layer 320 by using an inkjet print method or a
nozzle print method, for example, and drying it. The lens solution
used in forming the planarization layer 340 may be a hole injection
solution containing a hole injection material.
[0098] Since the lens solution used in forming the planarization
layer 340 may be the same as the lens solution used in forming the
lens layer 330, the lens solution may spread out to the edge of the
pixel opening 321 of the pixel defining layer 320 that has a
lyophilic property to the lens solution, so that the planarization
layer 140 has a shape with the center thinner than the edge.
However, the planarization layer 340 may have a flat surface by
adjusting drying conditions, such as adjusting a pressure for
drying the lens solution.
[0099] The hole transport layer 350, the light emitting layer 360,
the electron transport layer 370, the electron injection layer 380
and the second electrode 390 may be identical to the hole transport
layer 150, the light emitting layer 160, the electron transport
layer 170, the electron injection layer 180 and the second
electrode 190 shown in FIG. 2. Therefore, descriptions of the
identical elements will not be made to avoid redundancy.
[0100] As described above, according to the exemplary embodiment,
the light-emitting display device 300 may improve the viewing angle
by diffusing the light generated in the light emitting layer 360
toward the substrate 105 by virtue of the lens layer 330 that is
disposed on the first electrode 110 in the pixel opening 321 and
that works as a concave lens. Accordingly, the light-emitting
display device 300 may be used when a wide viewing angle is
required.
[0101] FIG. 8 is a cross-sectional view of a portion of a
light-emitting display device according to still another exemplary
embodiment, which corresponds to that shown in FIG. 2.
[0102] Referring to FIG. 8, a light-emitting display 400 according
to still another exemplary embodiment may include a substrate 105,
a first electrode 110, a pixel defining layer 420, a hole injection
layer 430, a hole transport layer 440, a light emitting layer 450,
an electron transport layer 460, an electron injection layer 470, a
second electrode 480, a partitioning wall 492, and a lens layer
494. The elements may be stacked on one another in the z-direction
of FIG. 8, for example.
[0103] The substrate 105 and the first electrode 110 have been
described above, and thus will not be described again.
[0104] The pixel defining layer 420 may be disposed on the first
surface 105a of the substrate 105 with a pixel opening 421 in which
the first electrode 110 may be exposed, and which defines each of
the pixels P (see FIG. 1) on the first surface 105a of the
substrate 105. The pixel defining layer 420 may be made of an
insulative material, for example.
[0105] The hole injection layer 430 may be disposed on the first
electrode 110 in the pixel opening 421 of the pixel defining layer
420.
[0106] The hole injection layer 430 may be formed by, but is not
limited to, an inkjet print method or a nozzle print method. For
example, the hole injection layer 430 may be formed by a deposition
method. The hole injection layer 430 plays the same role as that of
the hole injection layer comprised of the lens layer 130 and the
planarization layer 140 shown in FIG. 2; and, therefore, a
redundant description will be omitted.
[0107] The hole transport layer 440 may be disposed on the hole
injection layer 430 in the pixel opening 421 of the pixel defining
layer 420. The hole transport layer 440 may be identical to the
hole transport layer 150 shown in FIG. 2; and, therefore, a
redundant description will be omitted.
[0108] The light emitting layer 450 may be disposed on the hole
transport layer 440 in the pixel opening 421 of the pixel defining
layer 420. The light emitting layer 450 may be identical to the
light emitting layer 160 shown in FIG. 2; and, therefore, a
redundant description will be omitted.
[0109] The electron transport layer 460 may be disposed on the
light emitting layer 450. The electron transport layer 460 may be
identical to the electron transport layer 170 shown in FIG. 2; and,
therefore, a redundant description will be omitted.
[0110] The electron injection layer 470 may be disposed on the
electron transport layer 460. The electron injection layer 470 may
be identical to the electron injection layer 180 shown in FIG. 2;
and, therefore, a redundant description will be omitted.
[0111] The second electrode 480 may be disposed on the electron
injection layer 470. The second electrode 480 may be identical to
the second electrode 190 shown in FIG. 2; and, therefore, a
redundant description will be omitted.
[0112] The partitioning wall 492 may be disposed on the second
surface 105b of the substrate 105 and may have a partitioning wall
opening 492a exposing a part of the second surface 105b of the
substrate 105 corresponding to the first electrode. The
partitioning wall 492 defines pixels P (see FIG. 1) on the second
surface 105b of the substrate 105. The partitioning wall 492 may be
made of an insulative material, for example.
[0113] According to the exemplary embodiment, the lens solution has
a lyophilic property to the partitioning wall 492 such that the
lens layer 494 has the smallest thickness T41 in its center and the
largest thickness T42 at its edge. The lens layer 494 may be
produced via the process of forming the lens layer 494 by ejecting
a lens solution containing a lens material into the partitioning
wall opening 492a of the partitioning wall 492 using an inkjet
print method or a nozzle print method, for example. To this end,
the partitioning wall 492 may be made of an insulative material so
that the contact angle made by the partitioning wall 492 and the
lens solution may be about 10.degree. or less. The partitioning
wall 492 may be made of an organic insulative material, e.g., at
least one of benzocyclobutane (BCB), polyimide (PI), polyamide
(PA), acryl resin and phenol resin, or may be made of an inorganic
insulative material, e.g., at least one of silicon oxide, silicon
nitride and silicon oxynitride. The partitioning wall 492 may be
formed by, but is not limited to, a photolithography method.
[0114] The lens layer 494 may be disposed on the second surface
105b of the substrate 105 in the partitioning wall opening 492a.
The thickness of the lens layer 494 in its center may be different
from the thickness at its edge. The lens layer 494 may include a
transparent or transflective material which may work as a lens. The
lens layer 494 may have the smallest thickness T41 in its center
and may have the largest thickness T42 at its edge. A surface of
the lens layer 494 facing the second surface 105b of the substrate
105 may be a flat surface. The surface of the lens layer 494
exposed via the partitioning wall opening 492a may be a curved
surface being away from the light emitting layer 450 as it goes
from the center to the edge of the lens layer 494, for example, the
curved surface may be thicker at the edge. The lens layer 494 has
the curved surface so that it works as a convex lens. The lens
layer 494 concentrates the light that is generated in the light
emitting layer 450 to pass through the substrate 105 and then emit
it, thereby improving light extraction efficiency of the
light-emitting display device 400. Accordingly, the voltage applied
to the first electrode 110 and the second electrode 480 for
generating light in the light emitting layer 450 may be reduced
and, thus, the light-emitting display device 400 may be driven at a
lower power.
[0115] As described above, according to the exemplary embodiment,
the light-emitting display device 400 may include the lens layer
494 disposed on the second surface 105b of the substrate 105, so
that the light generated in the light emitting layer 450 may be
concentrated at an outermost surface of the substrate 105 when the
light is emitted toward the substrate 105, thereby further
improving the light extraction efficiency. Accordingly, the voltage
applied to the first electrode 110 and the second electrode 480 for
generating light in the light emitting layer 450 may be reduced
and, thus, the light-emitting display device 400 may be driven at a
lower power.
[0116] In addition, according to the exemplary embodiment, the
light-emitting display device 400 may include the lens layer 494
disposed on the second surface 105b of the substrate 105, so that
it is possible to learn the emission efficiency of the light
emitted from the light emitting layer 450 before forming the lens
layer 494. As a result, after determining the emission efficiency
of the light emitted, it is possible to form an appropriate lens
layer 494 for the emission efficiency of the light emitted from the
light emitting layer 450.
[0117] The lens layer 494 may be different in some pixels,
similarly to the lens layer 230 of the light-emitting display
device 200 shown in FIGS. 4 and 5. For example, the size of the
lens layer 494 in the first pixel P1 or the second pixel P2 may
differ from the size of the lens layer 494 in the third pixel P3.
For example, the smallest thickness of the lens layer 494 in its
center in the first pixel P1 or the second pixel P2 may differ from
the smallest thickness of the lens layer 494 in its center in the
third pixel P3.
[0118] FIG. 9 shows a cross-sectional view of a portion of a
light-emitting display device according to yet another exemplary
embodiment, which corresponds to that shown in FIG. 2.
[0119] Referring to FIG. 9, a light-emitting display 500 according
to yet another exemplary embodiment may include a substrate 105, a
first electrode 110, a pixel defining layer 420, a hole injection
layer 430, a hole transport layer 440, a light emitting layer 450,
an electron transport layer 460, an electron injection layer 470, a
second electrode 480, a partitioning wall 592, and a lens layer
594. The elements may be stacked on one another in the z-direction
of FIG. 9, for example.
[0120] The substrate 105, the first electrode 110, the pixel
defining layer 420, the hole injection layer 430, the hole
transport layer 440, the light emitting layer 450, the electron
transport layer 460, the electron injection layer 470 and the
second electrode 480 have described above and, therefore, will not
be described again to avoid redundancy.
[0121] The partitioning wall 592 may be disposed on the second
surface 105b of the substrate 105 and may have a partitioning wall
opening 592a exposing a part of the second surface 105b of the
substrate 105 corresponding the first electrode 110. The
partitioning wall 592 defines pixels P (see FIG. 1) on the second
surface 105b of the substrate 105. The partitioning wall 592 may be
made of an insulative material, for example.
[0122] According to the exemplary embodiment, the lens solution may
have a lyophobic property to the partitioning wall 592 such that,
in the process of forming the lens layer 594, the lens layer 594
may be formed such that it has the largest thickness T51 in its
center and the smallest thickness T52 at its edge. The lens layer
594 may be formed by ejecting a lens solution containing a lens
material into the partitioning wall opening 592a of the
partitioning wall 592 using an inkjet print method or a nozzle
print method, for example. To this end. the partitioning wall 592
may be made of an insulative material so that the contact angle
made by the partitioning wall 592 and the lens solution may be
about 50.degree. or greater. The partitioning wall 592 may be made
of an organic insulative material such as a polymer resin
containing fluorine, e.g., at least one of benzocyclobutane (BCB),
polyimide (PI), polyamide (PA), acryl resin, and phenol resin. The
partitioning wall 592 may be formed by, but is not limited to, a
photolithography method.
[0123] The lens layer 594 may be disposed on the second surface
105b of the substrate 105 in the partitioning wall opening 592a.
The thickness of the lens layer 594 in its center may be different
from the thickness at its edge. The lens layer 594 may have the
largest thickness T51 in its center and may have the smallest
thickness T52 at its edge. A surface of the lens layer 594 facing
the second surface 105b of the substrate 105 may be a flat surface.
The surface of the lens layer 594 exposed via the partitioning wall
opening 592a may be a curved surface being closer to the light
emitting layer 450 as it goes from the center to the edge of the
lens layer 594, for example, the curved surface may be thicker in
the center. The lens layer 594 may have the curved surface so that
it works as a concave lens. The lens layer 594 may diffuse the
light that is generated in the light emitting layer 450 toward the
substrate 105, thereby improving the viewing angle of the
light-emitting display device 500.
[0124] As described above, according to the exemplary embodiment,
the light-emitting display device 500 may include the lens layer
594 disposed on the second surface 105b of the substrate 105, so
that the light generated in the light emitting layer 450 may be
diffused at the outermost surface of the substrate 105 when the
light is emitted toward the substrate 105, thereby further
improving the viewing angle.
[0125] Hereinafter, a method for fabricating the light-emitting
display device according to the exemplary embodiments will be
described.
[0126] FIGS. 10 to 17 are cross-sectional views and perspective
views for illustrating processes of a method for fabricating a
light-emitting display device according to an exemplary
embodiment.
[0127] Referring to FIG. 10, a first electrode 110 may be formed in
each of a plurality of pixels P (see FIG. 1) defined on a first
surface 105a of a substrate 105. The first electrode 110 may be
formed by depositing a transparent electrode material or a
reflective material on the substrate 105 to pattern it. In the
exemplary embodiment, the first electrode 110 may be made of a
transparent electrode material.
[0128] Referring to FIG. 11. a pixel defining layer 120 may be
formed, which defines each of the pixels P (see FIG. 1) on the
substrate and has a pixel opening in which the first electrode 110
may be exposed. The pixel defining layer 120 may be formed, for
example, by depositing an insulative material on the entire surface
of the first surface 105a of the substrate 105 by using a
deposition method so that it covers the first electrode 110 and
patterning the deposited, insulative material.
[0129] The pixel defining layer 120 may be formed by an insulative
material that has a lyophobic property to the lens solution 130a
(see FIG. 12) by using an inkjet print method or a nozzle print
method, for example, so that the lens layer 130 has the largest
thickness in its center T1 (see FIG. 3) and the smallest thickness
T2 (see FIG. 3) at its edge. Alternatively, the pixel defining
layer may be formed by an insulative material that has a lyophilic
property to a lens solution, so that the lens layer 130 has the
smallest thickness in its center and the largest thickness at its
edge.
[0130] Referring to FIGS. 12 and 13, the lens layer 130 may be
formed on the first electrode 110 in the pixel opening 121.
[0131] As shown in FIG. 12, a lens solution 130a containing a lens
material may be ejected into the pixel opening 121 of the pixel
defining layer 120 by using an inkjet print method or a nozzle
print method, for example. Since the pixel defining layer 120 has a
lyophobic property to the lens solution 130a, the lens solution
130a may have a convex shape with the center thicker than the edge
without spreading out to the edge on the first electrode 110. The
lens solution 130a may be dried, forming the lens layer 130 shown
in FIG. 13. The lens layer 130 may be formed, for example, by a
simple print method by varying a contact angle made by the lens
solution 130a and the pixel defining layer 130, without requiring
any dedicated patterning.
[0132] Referring to FIGS. 14 and 15, a planarization layer 140
having a flat surface may be formed on the lens layer 130 in the
pixel opening 121.
[0133] As shown in FIG. 14, a lens solution 140a containing a lens
material may be ejected into the pixel opening 121 of the pixel
defining layer 120 by using an inkjet print method or a nozzle
print method, for example. The lens solution 140a may be dried,
forming the planarization layer 140 shown in FIG. 15. The lens
solution 140a may be the same as the lens solution 130a (see FIG.
12) used in forming the lens layer 130 (see FIG. 13). The flat
surface of the planarization layer 140 may be formed by adjusting
drying conditions of the lens solution 140a.
[0134] Referring to FIG. 16, a hole transport layer 150 may be
formed on the planarization layer 140, and a light emitting layer
160 may be formed on the hole transport layer 150. The hole
transport layer 150 and the light emitting layer 160 may be formed
by, but are not limited to, an inkjet print method or a nozzle
print method. For example, the hole transport layer 150 and the
light emitting layer 160 may be formed by a deposition method.
[0135] Referring to FIG. 17, an electron transport layer 170 may be
formed on the light emitting layer 160, an electron injecting layer
180 may be formed on the electron transport layer 170, and a second
electrode 190 may be formed on the electron injecting layer 180.
The electron transport layer 170, the electron injecting layer 180
and the second electrode 190 may be formed by a deposition process,
for example.
[0136] The method of fabricating a light-emitting display device
according to an exemplary embodiment may further include disposing
a sealing substrate on the second electrode 190. In addition, the
method of fabricating a light-emitting display device according to
an exemplary embodiment may further include disposing a spacer
between the sealing substrate and the second electrode 190. A
suitable method of disposing the sealing substrate and the spacer
may be used.
[0137] By way of Summation and review, an organic light-emitting
display device may include a lens layer disposed on the substrate
that may improve the extraction efficiency of light emitted from a
light emitting layer or may improve the viewing angle. The lens
layer may be formed by a photolithography process using a photo
mask.
[0138] However, such a photolithography process using a photo mask
may be complicated. Moreover, the shape and size of a lens layer
may need to change depending on characteristics of an organic
light-emitting display device, e.g., different light extraction
efficiency or viewing angle. To that end, the photo mask may need
to be replaced, which may be cumbersome.
[0139] Exemplary embodiments may provide a light-emitting display
device including a lens layer that may be formed by a simple
method, and may improve light extraction efficiency or viewing
angle.
[0140] Exemplary embodiments may also provide a method of
fabricating a light-emitting display device including a lens layer
that may be formed by a simple method, and may improve light
extraction efficiency or viewing angle.
[0141] Exemplary embodiments may provide a light-emitting display
device that may improve light extraction efficiency or viewing
angle by virtue of a lens layer that may be formed by a simple
method.
[0142] Example embodiments have been disclosed herein, and although
specific terms are employed, they are used and are to be
interpreted in a generic and descriptive sense only and not for
purpose of limitation. In some instances, as would be apparent to
one of ordinary skill in the art as of the filing of the present
application, features, characteristics, and/or elements described
in connection with a particular embodiment may be used singly or in
combination with features, characteristics, and/or elements
described in connection with other embodiments unless otherwise
specifically indicated. Accordingly, it will be understood by those
of skill in the art that various changes in form and details may be
made without departing from the spirit and scope of the present
invention as set forth in the following claims.
* * * * *